An entry does not become final when the goods clear. It liquidates later, when CBP formally closes the entry and fixes the duty, and that date, published in the liquidation notices and visible in the importers account data, starts the 180 day protest period. Importers who watch clearance dates and ignore liquidation dates discover their refund rights after they have expired, which is the most common and most preventable protest failure.
Diarise liquidation for entries carrying real money: contested classifications, preference claims made under pressure, values the broker queried. The diary entry is cheap. Its absence converts correctable errors into donations. Brokers track liquidation as part of their service, but the duty is the importers and so is the loss when a deadline passes unremarked by either party. Confirm who is watching, in writing.
A protest states the decision objected to, the claim, and the grounds, with enough specificity that CBP can decide it. For a classification protest that means the competing headings, the reasoning from the tariff text and rulings, and the physical facts of the article. A protest that says duty too high, reclassify, invites a denial that is hard to appeal because nothing was ever actually argued.
Evidence goes in with the protest or in support within the rules: product specifications, samples where useful, photographs, prior rulings on the same or comparable goods, and the entry documents as filed. Where the same error repeats across entries, a protest can cover the pattern, and a claim for further review can put a novel legal question in front of headquarters rather than leaving it at the port.
Before liquidation, post summary correction is faster and simpler for clerical and classification errors on entries still open. After liquidation, the protest is the vehicle. Where the error is the importers own material mistake, discovered before CBP finds it, a prior disclosure may be the safer frame because it addresses penalty exposure as well as the duty, and the two questions should never be separated just because the refund looks attractive.
Drawback is a different refund entirely, tied to export or destruction of imported goods, with its own claims and clocks. Importers sometimes file protest language for what is really a drawback claim and lose time on both. The first question in any refund conversation is which instrument fits these facts, and it is a broker or counsel question, answered before anything is filed.
A denied protest can be taken to the Court of International Trade, generally within 180 days of the denial notice, which makes the protest itself the foundation of the court case: grounds not raised are hard to add later. That is the practical reason protests deserve drafting care out of proportion to their form length. You are not filling in a form. You are writing the first pleading.
Keep the full file together: entry, liquidation notice, protest, evidence, denial. Refund money, when it comes, arrives with interest rules and offsets that accounting will need to reconcile against the original duty payments, and a file that has to be reconstructed from email will cost more than the interest earns.
Keep reading: How do Section 301 exclusions expire, and what should importers file before they do?, How do importers use bonded warehouses to delay duty when cash is tight?.
Generally 180 days from the date of liquidation of the entry. Liquidation, not clearance and not the duty payment date, starts the clock, which is why tracking liquidation status matters for any entry with a material error.
If the entry has not yet liquidated, a post summary correction is usually the simpler route. After liquidation, the protest is the formal vehicle for challenging the classification, value, or other decision CBP made.
The competing tariff provisions, reasoning grounded in the tariff text, notes, and rulings, and the physical facts and evidence for the actual article. Vague objections are routinely denied and are difficult to revive on appeal.
Not by itself. Where the error is a material misstatement by the importer, penalty exposure is a separate question and a prior disclosure may be the appropriate step. Take broker or counsel advice before filing anything that describes the error.